1. Field of the Invention
The invention relates to a leakage testing tool for a bellow of a semiconductor manufacturing machine, especially to a testing tool which can quickly and conveniently determine if a bellow is damaged or not, and therefore can significantly achieve a low production cost.
2. Description of Related Art
Bellows are used in semiconductor manufacturing machines for keeping chambers of the machines in vacuum. Shown in FIG. 4 is one kind of semiconductor manufacturing machine, a rapid thermal processor. It consists of a seat (50) and a cover (54) pivotally linked to the seat (50); the cover (54) is able to cover the seat (50) to form a chamber therebetween. The seat (50) has an inner disc (53) and a passage (52). A plurality of holes (51) are defined in the inner disc (53) for containing corresponding supporting needles (not shown in this FIG.). The cover (54) has a bulb group (55) which when the cover (54) is closed on to the seat (50), is just above the inner disc (53).
In production, as shown in FIG. 5 in which a conveyance tunnel is connected to a left side of the machine, a valve (61) provided in the tunnel is opened and a crystal unit (70) is put by a mechanical arm (60) through the passage (52) into the chamber. In FIG. 6, the supporting needles (512) are pushed to stick out from the inner disc (53) to support the crystal unit (70) and the mechanical arm (60) is drawn back. In FIG. 7, the valve (61) is closed. In FIG. 8, the rapid thermal processor is actuated. In FIG. 9, purge gas enters and flows through the processor. In FIG. 10, the valve (61) is opened again and the mechanical arm (60) is put into the chamber again. And finally in FIG. 11, the crystal unit is brought away by the mechanical arm (60) and the valve (61) is closed.
As described above, the supporting needles (512) should be pushed into the chamber and pulled back at least one time within one process. As shown in FIG. 12, each needle (512) is formed on a needle seat (513) and could be inserted through a channel (511) and the hole (51) defined in the inner disc (53). In order to prevent air leakage from the holes (51) and the channel (511), a bellow (20) is put round each needle (512) prior to the insertion. The bellow (20) has a top flange (22) and a bottom flange (23) which are able to respectively press on a bottom surface of the inner disc (53) and a top surface of the needle seat (513), and which, by assistance from two seal rings provided on top of each flange (22, 23), can keep the vacuum in the chamber.
In production, the bellows (20) are very liable to be damaged because of frequent movement. About two bellows (20) will be destroyed in one machine within one year. In a conventional test, two leakage tests, wherein all the needles (512) are pushed up and when all needles (512) are pulled back, are respectively conducted and then the results are compared. If the difference between the two results is greater than a standard one, it is deemed a leakage occurred and then all the bellows (512) must be changed.
The main objective of the invention is to provide a leakage test tool which can quickly and conveniently determine if a bellow is damaged or not, and therefore can achieve a significant low production cost. To obtain the above objective, a leakage testing tool for a bellow of a semiconductor manufacturing machine is provided to have a base, a first rack and a second rack opposite the first rack. Both racks are formed on the base and each of the racks have a recess defined to receive a bellow defining a central bore. The tool further comprises two opposite ears formed on the base respectively outside of the first and the second rack and each of the ears defining a threaded hole. Two adjustment screws are respectively threaded in said threaded holes of the ears. The tool also has a first and a second movable plates each having a flat end face urging against a respective one of two end flanges of the bellow, and each being able to engage with an adjustment screw. A tube is formed on a side wall of the first movable plate. One end of the tube is hermetically connected to a leakage detector and another end of the tube is in communication with a hole defined in the first movable plate which is in communication with the central bore of the bellow, whereby when the combined bellow and leakage testing tool are disposed in an airtight chamber which is then charged with a gas, a hermetic quality of the bellow is determinable.
Other objects, advantages and novel features of the invention will become more apparent from the following detailed description when taken in conjunction with the accompanying drawings.